From patchwork Mon Jul 27 06:16:55 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Archit Taneja X-Patchwork-Id: 6869061 Return-Path: X-Original-To: patchwork-dri-devel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 02BB99F380 for ; Mon, 27 Jul 2015 06:17:17 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 2BEED20628 for ; Mon, 27 Jul 2015 06:17:16 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) by mail.kernel.org (Postfix) with ESMTP id 6E13D2062B for ; Mon, 27 Jul 2015 06:17:13 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id C0E166E7FA; Sun, 26 Jul 2015 23:17:12 -0700 (PDT) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from smtp.codeaurora.org (smtp.codeaurora.org [198.145.29.96]) by gabe.freedesktop.org (Postfix) with ESMTPS id 1B0046E7FA for ; Sun, 26 Jul 2015 23:17:11 -0700 (PDT) Received: from smtp.codeaurora.org (localhost [127.0.0.1]) by smtp.codeaurora.org (Postfix) with ESMTP id B654D140FA9; Mon, 27 Jul 2015 06:17:10 +0000 (UTC) Received: by smtp.codeaurora.org (Postfix, from userid 486) id 7BEE6140FB0; Mon, 27 Jul 2015 06:17:10 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Spam-Level: X-Spam-Status: No, score=-5.5 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 Received: from localhost (unknown [202.46.23.61]) (using TLSv1.2 with cipher DHE-RSA-AES128-SHA (128/128 bits)) (No client certificate requested) (Authenticated sender: architt@smtp.codeaurora.org) by smtp.codeaurora.org (Postfix) with ESMTPSA id 9E3ED140FA9; Mon, 27 Jul 2015 06:17:07 +0000 (UTC) From: Archit Taneja To: dri-devel@lists.freedesktop.org, lars@metafoo.de Subject: [PATCH 1/5] drm/i2c: adv7511: Fix mutex deadlock when interrupts are disabled Date: Mon, 27 Jul 2015 11:46:55 +0530 Message-Id: <1437977819-24199-2-git-send-email-architt@codeaurora.org> X-Mailer: git-send-email 1.8.2.1 In-Reply-To: <1437977819-24199-1-git-send-email-architt@codeaurora.org> References: <1437977819-24199-1-git-send-email-architt@codeaurora.org> X-Virus-Scanned: ClamAV using ClamSMTP Cc: linux-arm-msm@vger.kernel.org, andy.green@linaro.org, srinivas.kandagatla@linaro.org, laurent.pinchart@ideasonboard.com X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" X-Virus-Scanned: ClamAV using ClamSMTP When the adv7511 i2c client doesn't have an interrupt line, we observe a deadlock on caused by trying to lock drm device's mode_config.mutex twice in the same context. Here is the sequence that causes it: ioctl DRM_IOCTL_MODE_GETCONNECTOR from userspace drm_mode_getconnector (acquires mode_config mutex) connector->fill_modes() drm_helper_probe_single_connector_modes connector_funcs->get_modes adv7511_encoder_get_modes adv7511_get_edid_block adv7511_irq_process drm_helper_hpd_irq_event (acquires mode_config mutex again) In adv7511_irq_process, don't call drm_helper_hpd_irq_event when not called from interrupt context. It doesn't serve any purpose there anyway. Signed-off-by: Archit Taneja --- drivers/gpu/drm/i2c/adv7511.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/i2c/adv7511.c b/drivers/gpu/drm/i2c/adv7511.c index 2aaa3c8..cf5bb29 100644 --- a/drivers/gpu/drm/i2c/adv7511.c +++ b/drivers/gpu/drm/i2c/adv7511.c @@ -422,7 +422,7 @@ static bool adv7511_hpd(struct adv7511 *adv7511) return false; } -static int adv7511_irq_process(struct adv7511 *adv7511) +static int adv7511_irq_process(struct adv7511 *adv7511, bool process_hpd) { unsigned int irq0, irq1; int ret; @@ -438,7 +438,7 @@ static int adv7511_irq_process(struct adv7511 *adv7511) regmap_write(adv7511->regmap, ADV7511_REG_INT(0), irq0); regmap_write(adv7511->regmap, ADV7511_REG_INT(1), irq1); - if (irq0 & ADV7511_INT0_HDP && adv7511->encoder) + if (process_hpd && irq0 & ADV7511_INT0_HDP && adv7511->encoder) drm_helper_hpd_irq_event(adv7511->encoder->dev); if (irq0 & ADV7511_INT0_EDID_READY || irq1 & ADV7511_INT1_DDC_ERROR) { @@ -456,7 +456,7 @@ static irqreturn_t adv7511_irq_handler(int irq, void *devid) struct adv7511 *adv7511 = devid; int ret; - ret = adv7511_irq_process(adv7511); + ret = adv7511_irq_process(adv7511, true); return ret < 0 ? IRQ_NONE : IRQ_HANDLED; } @@ -473,7 +473,7 @@ static int adv7511_wait_for_edid(struct adv7511 *adv7511, int timeout) adv7511->edid_read, msecs_to_jiffies(timeout)); } else { for (; timeout > 0; timeout -= 25) { - ret = adv7511_irq_process(adv7511); + ret = adv7511_irq_process(adv7511, false); if (ret < 0) break;